Final keyword explained

What is Final Keyword in Java?

The final keyword in Java is a non-access modifier used to impose restrictions. Depending on where it is used, it prevents:

• Reassignment (for variables),
• Overriding (for methods),
• Inheritance (for classes).

It is mainly used to make code more secure, consistent, and predictable.

📌 We declare final in the following:

1. Final Variable
2. Final Method
3. Final Class

Final Variable

A variable marked as final cannot be re-assigned once it has been initialized. It effectively becomes a constant.

public class Main{
  public static void main(String[] args){
     double pi = 3.14;
     System.out.println("Original pi value: " + pi);

     // Reassigning pi
     pi = 3.14159;
     System.out.println("Modified pi value: " + pi);
  }
}

The above code shows how a fixed variable can be accidentally changed by another developer who is unaware of it. Using the final keyword prevents this from happening.

public class Main{
  public static void main(String[] args){
     final double PI = 3.14;
      System.out.println("Pi value: " + PI)…